Apparatus for packaging articles



I Nov. 30, 1965 M. E. WALLIS 3,220,379

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United' States Patent C) 3,220,379 APPARATUS FOR PACKAGING ARTICLES Marvin E. Wallis, 1643 Woodland Drive, San Luis Obispo, Calif. Filed Nov. 14, 1963, Ser. No. 323,779 5 Claims. (Cl. 118-16) This invention relates to packaging machines and refers more particularly to machines especially adapted for the packaging of comestible articles of goods in accordance with the packaging method disclosed and claimed in applicants Patent No. 3,008,834. This application is a continuation-in-part of applicants copending application Serial No. 16,352, filed March 21, 1960, now abandoned, and said copending application was a continuationin-part of the application maturing into the aforesaid patent.

The method disclosed in that patent briefly consists in projecting a plurality of spaced apart film-like sheets of a thermoplastic coating material which is a viscous liquid at elevated temperatures and a solid at ordinary room temperatures, into a heated coating zone, and moving the comestible articles or goods to be packaged successively through these flowing sheets. Each film-like sheet issues from a separate nozzle which has means to form the discharging liquid into a generally vertically disposed sheet with divergent edges. As the articles or goods pass through each sheet of viscous liquid, the sheet lays itself onto those surfaces thereof which oppose the direction of flow of the liquid comprising the sheet. Thus, by having the nozzles disposed above and at opposite sides of the path of the articles or goods to be packaged, the top and sides thereof become coated and covered by this viscous material.

The underside or bottom of the articles or goods is coated with viscous liquid projected upwardly in the form of a plurality of small upwardly directed jets or in the form of a film-like sheet from a separate nozzle. It is possible, therefore, with the method of the aforesaid patent to cover all surfaces of an article or to have different surfaces of the comestible articles or other goods covered by different colored coating material or, for instance, to have some of the surfaces covered by a transparent coating while others are covered by an opaque coating.

Since the film-like sheets lay themselves onto the surfaces of the articles or goods without breaking, regardless of the contour of the surfaces, the shells or sheaths formed about the articles or goods have substantially uniform thickness. Depressions or hollows do not fill up and the covering over the high spots is not stretched thin. Also, by simply increasing the number of the film-like sheets through which the product moves, the wall thickness of the enveloping shell or sheath may be increased since the successive sheets weld to one another despite the relatively rapid rate at which they harden.

It is another feature of the invention that the junctions of the coating on the top and bottom surfaces with that of the side surfaces always will be uniformly smooth and neat. But to assure this desired result at the bottom edges as well as at the top edges, it is necessary that the flowing sheets which are projected from the opposite sides of the path of the advancing articles or goods, have their lower edges disposed below the undersides or bottoms thereof as the articles or goods move through these sheets. Unless this requirement is met, the coating on the side surfaces will not have the desired uniform thickness and, instead, an unsightly and irregular thickening occurs at the bottom which has been characterized as run down. The avoidance of this objectionable condition presented a problem in the past, the solution of which is one of the 3,220,379" Patented Nov. 30, 1965 major purposes of the herein presented improvement over the invention as disclosed in the aforesaid application.

Accordingly, the improvement of the present invention has as its primary purpose and objective to provide a conveyor to carry the articles or other goods through the machine, which is so designed and constructed that it allows the flowing sheets of viscous liquid which are projected from nozzles located at opposite sides of the conveyor, to extend uninterruptedly across the path of the articles or goods on the conveyor, with the lower edges of the sheets below the level of the conveyor surface so that as the articles or goods are advanced they move through the sheets, and the lower edge portions of the sheets as well as their upper portions remain continuous and unbroken. This assures a proper bond between the coating at the underside or bottom of the articles or goods and the coating covering the sides thereof, and in general achieves a much better package.

More specifically, it is an object of this invention to provide an improved conveyor for the purpose described which is characterized by a gap in its article supporting stretch extending transversely thereacross in line with each of the nozzles from which the coating material is projected, and to have the nozzles so located and disposed with respect to the conveyor that the thin, substantially vertically disposed sheets issuing from the nozzles have their lower portions received in these gaps.

Still more specifically, it is an object of this invention to provide a conveyor which consists essentially of a plurality of side-by-side endless chains trained about sprockets or pulleys and riding upon fixed tracks with the tracks and sprockets or pulleys so disposed and arranged that gaps are formed transversely across the article support provided by the conveyor, by interruptions in the tracks and by training the chains around idler sprockets or pulleys located at these interruptions and wholly below the track level.

Another object of this invention is to provide a conveyor of the character desired with one or more gaps extending transversely across its article support and wherein these gaps may be disposed at right angles to the path of the conveyor or at an oblique angle thereto.

Another object of this invention is to provide an improved way of coating the bottom or underside of the I goods to be packaged.

A further object of this invention and particularly of that embodiment thereof which is disclosed in the aforesaid application, is to provide novel means whereby the positions of the various nozzles or film heads as they are termed in said application, as well as their angularity with respect to the path of travel of the articles of goods through the machine, may be varied to accommodate different sizes and styles of articles and goods without necessitating complete shutting down of the machine.

With the above and other objects in view which will appear as the description proceeds, this invention resides in the novel means substantially as hereinafter described and more particularly defined in the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate several complete examples of the physical embodiment of the invention constructed according to the best modes so far devised for the practical application of the principles thereof, and in which:

FIGURE 1 is a fragmentary perspective view, somewhat schematic in its representation, illustrating one form of apparatus by means of which the packaging method of the present invention may be carried out;

FIGURE 2 is an enlarged sectional view taken sub- 3 stantially along the vertical plane indicated by the line 22 of FIGURE 1;

FIGURE 3 is a fragmentary perspective view of a vertically adjustable bottom coating thickness control mechanism employed in connection with the present invention;

FIGURE 4 is an enlarged sectional view taken substantially along the vertical plane indicated by the line 44 of FIGURE 1;

FIGURE 5 is a sectional view taken substantially along the line 55 of FIGURE 4;

FIGURE 6 is an enlarged sectional view taken substantially along the vertical plane indicated by the line 6-6 of FIGURE 1;

FIGURE 7 is a schematic view of the apparatus illustrating principally the hydraulic system associated therewith;

FIGURE 8 is an enlarged fragmentary detail perspective view of a portion of the apparatus illustrating the manner in which certain of the film-forming nozzles associated with the same may be adjusted;

FIGURE 9 is an enlarge-d detail fragmentary perspective view of a portion of the structure shown in FIG- URE 8;

FIGURE 10 is an enlarged detail fragmentary perspective view of another portion of the structure shown in FIGURE 8;

FIGURE 11 is a perspective view of one of the filmproducing nozzles or film heads employed in connection with the present invention;

FIGURE 12 is a perspective view, generally illustrating the improved machine of this invention;

FIGURE 13 is a perspective view upon a larger scale, of the main portion of the machine;

FIGURE 14 is a plan view of the portion of the machine shown in FIGURE 13;

FIGURE 15 is a longitudinal sectional view through FIGURE 14 on the plane of the line 1515;

FIGURE 16 is a longitudinal sectional view through FIGURE 14 on the plane of the line 16-46.

FIGURE 17 is a cross sectional view through the machine, taken on the plane of the line 1717 in FIGURE 14 and illustrating how the lower portion of the sheets issuing from the nozzles at the sides of the machine continue uninterruptedly beneath the article being packaged, as a consequence of its being received in a gap inthe article supporting or carrying stretch of the conveyor;

FIGURE. 18 is across sectional view through the machine, on the plane of the line 18-18 in FIGURE 14, with parts broken away to show details of construction;

FIGURE 19 is a longitudinal sectional view through the top coating station of the machine, slightly modified to, adapt the same to the use of certain coating materials which are difiicult to handle and keep in the liquid state, as for instance pure lower molecular weight polyethylene and other exceptionally viscous materials at application temperatures;

FIGURE 20 is a side elevational view illustrating another embodiment of the invention for coating of the article bottoms; and

FIGURE 21 is an end elevational view of the film for coating article bottoms and taken substantially along line 21-21 of FIGURE 20.

Referring. now to the drawings in detail, and, in particular, to FIGURES 1 and 2 (which illustrate generally one form of the apparatus or machine embodying this invention), it will be seen that the comestibles or other articles A to be packaged, are carried upon a moving endless conveyor band 10, associated with a conveyor assembly 11. The forward end of the conveyor band passes over an idler roller or drum 12, and the rear end thereof passes over a driving roller or drum 14. The rollers 12 and 14 are suitably mounted on shafts 16 and 18, respectively, which shafts are adapted to be rotatably journalled in the framework of the machine.

The complete machine framework is not disclosed in the schematic illustration of the invention, and only portions thereof appear at selected locations in the various views of the drawings, the reference numeral 20 being applied in each instance to the illustrated portion of the framework. The shaft 18 constitutes the driving shaft for the conveyor assembly 11, and it is adapted to be driven by a belt and pulley arrangement 22 from an electric motor 24 suitably carried on the machine framework.

The endless conveyor band 10 has an upper straightaway portion 26 and a lower return portion 28. In its medial region, the straightaway portion 26 is interrupted by a dip, so to speak, as at 30 (see particularly FIGURE 2), and this downwardly displaced portion 30 partially encloses one form of a bottom coating device, designated in its entirety by the numeral 32. The interruption thus provided in the medial region of the straightaway portion 26 divides the same into a forward section 26a and a rear section 2612, the former being in register at its extreme forward end with a feed table 33, and the latter being in register at its rearmost end with a straightaway portion 34 of an endless belt 36 associated with a discharge conveyor assembly 38, only a portion of which has been shown in FIGURE 1. The forward end of the endless belt 36 passes over a roller or drum 40 suitably journalled in the machine framework. The conveyor band 10 is preferably formed of stainless steel wire mesh material and its direction of movement is illustrated by the arrows in FIGURE 1, as is also the direction of movement of the endless conveyor belt 36.

The conveyor assembly 11 is enslosed within a gener ally rectangular casing or cabinet, the outlines of which are shown in dotted lines at 42. The details of the casing 42 form no part of the present invention, and it will be understood that the same will, of course, be provided with suitable entrance and exit openings in the front and rear walls thereof for introduction of the articles A undergoing packaging to the forward end of the conveyor 11 and for transfer of the packaged articles from the rear end of the conveyor 11 to the discharge conveyor 38, the latter conveyor being disposed exten'orly of the casing 42.

The casing 42 may be formed of stainless sheet steel and the top and side walls thereof may be provided with one or more cover plates and access openings at appro-- priate regions therein. The casing 42 serves the multiplepurpose of shielding the internal operative packaging mechanism, including the conveyor assembly 11 and the articles undergoing packaging thereon from contamination and from the effects of ambient conditions of temperature and humidity, of retaining the heat generated within the casing 42 for film conditioning purposes, and of serving as a splash guard for preventing egress of the film forming liquid from the immediate vicinity of the apparatus, either during operation of the apparatus or during adjustment of the various film-producing nozzles or film heads.

The articles A which, for illustrative purposes, may be in the form of stacks of sliced luncheon meat with the individual slices thereof being generally of rectangular configuration, so that the finished package will be of rectilinear design, are fed to the conveyor and are adapted to progress along the straightaway portion 26 of the conveyor band 10 from a point of entrance into the casing 42 to a point of discharge where the completely packaged articles pass over a bottom film thickness con trol mechanism 43 which has been illustrated in detail in FIGURE 3, and are transferred to the discharge conveyor 38.

In passing along the straightaway'p'ortion 26 of the conveyor 10, the various articles A encounter a plurality of flowing liquid films, or film-like sheets, six such films being illustrated herein, and being designated at f1, f2, f3, f4, f5 and f6, respectively. These films issue from a' series of six r'iozzle's or film heads 44, 46, 48, 0, 52 and 54, respectively, with the film heads being arranged along the straightaway portion 26 of the conveyor in longitudially spaced relationship sequentially in the order named. The various film heads may be substantially identical in construction, although the specific design of the same may, if desired, be varied so as to produce films having different characteristics. One of the nozzles, namely, the nozzle 44, has been shown in detail in FIG- URE 11, and the character and function thereof will be described subsequently. While six such nozzles and the films issuing therefrom have been illustrated herein by way of example, it will be understood that a greater or lesser number of such film heads may be employed if desired to.accommodate various types of package coatings on the articles, as well as to accommodate differently shaped articles. Ordinarily, however, it will be found that for articles of a polygonal nature, with either planar or curved sides, the use of four side and one top such film heads properly arranged along the conveyor straightaway portion 26, will sutfice to apply a dual thickness package coating to the exposed sides and tops of the articles in a manner that will be made clear presently.

The composition of the liquid films issuing from the various film heads may vary widely, but in general a compounded liq-uid wax having a medium or high viscosity and having a melting point in the neighborhood of 150 F. will be found suitable for application to comestibles, particularly edible meats which are processed at low temperatures, i.e., frozen meats and the like. Numerous compositions have been found suitable as a packaging coating for such comestibles, and it will be understood that the particular composition selected will vary according to the article to which it is to be applied and also according to the quality and physical characteristics of the package coating desired.

Certain liquid materials when applied to the articles A and hardened thereon, will be almost completely transparent, while other films will present a package coating which is translucent or opaque. The liquid materials employed for the films may also vary as to color, and various shades or films are contemplated by the use of suitable coloring additives. In addition to wax base films, various plastic materials such as polyethylene and the like have been found suitable for use in connection with the packaging of comestibles.

One specific material capable of use in connection with the present invention as a film material, and consequently as a hardened package coating for comestibles of the type here under consideration, is a microcrystalline wax derived from a parafiin base crude oil, plasticized with butyl rubber or thickening material to increase viscosity. As a wax coating this material has extremely high tensile strength and a low coefficient of expansion. Another specific material which has been found suitable as a film material according to the present process of packaging comestibles, such as frozen or chilled meats and the like, consists of acetylated monoglycerides and ethyl cellulose, combined in a manner which will produce a high viscosity film which, when hardened as a coating for the articles, also has high tensile strength and a low coefficient of expansion, as Well as a relatively low melting point.

No claim as made herein to any novelty associated with the particular material used for the fluid films f1, f2, f3, etc., or to the specific coating produced thereby when these films have become hardened on the articles A, since various other materials are available for use and still other materials may be developed by experimentation which will subsequently be found suitable. It is deemed sufiicient for purposes of description herein to state that the particular liquid material employed must possess a relatively high viscosity at the low temperatures involved while the material is in film form so that it will have sufiicient tenacity to hold together as a solid unbroken sheet over an area at least as large as the sur- 6 face or surfaces of the article to which it is to be applied, and it must also have high tensile strength when hardened on the surface of the article to avoid rupture under normal conditions of handling of the packaged product.

Additionally, the film, in its hardened state as a coating material must be non-toxic, odorless, tasteless, have a low coefficient of expansion upon hardening so as to avoid the production of cracks or fractors in the coating, be chemically inert with respect to the substance to which it is applied, and be impervious to moisture and exhibits no osmotic tendencies. Finally, the hardened coating must possess sufficient tensile strength that it may readily be stripped from the comestible to render the latter accessible for use. Irrespective, however, of the particular composition employed for the various films f1, f2, f3, etc., the essential features of the invention are at all times preserved.

Still referring to FIGURE 1, the various film heads 44, 46, 48, 50, 52 and 54 are disposed in the vicinity of the straightaway portion 26 of the conveyor 11 in positions where they will direct their streams of liquid inwardly toward the path of travel of the articles A at different angles and in different directions, generally horizontally against the sides of the articles passing along the conveyor and generally vertically downwardly against the tops of the articles. Collectively, the five or six nozzles or film heads are adapted to apply a uniform continuous imperforate coating to the four sides and top of each article passing through the casing or cabinet 42 on the conveyor 11 by a two-stage coating process, while the bottom coating mechanism 32 is adapted to apply a uniform homogenous imperforate coating to the bottom of the article, this latter coating automatically becoming sealed to the side coatings so that the four side coatings, the top coating and the bottom coating constitutes a sealed enclosure or envelope for the article, the six sides thereof having intimate coextensive cont-act with the side faces of the article.

As will become apparent presently when the nature of the invention is better understood, the coating or covering which is thus applied to the article on all sides or surfaces thereof is of a unique character in that it is of uniform thickness throughout, regardless of the contour of the surfaces of the article. The coating or covering is thus to be distinguished from the type of coating which is ordinarily applied to articles by so-called enrobing machines wherein a heavy stream or ribbon of the coating material is directed or poured on the articles or cores and allowed to settle around the four sides thereof, thus filling all voids completely.

The various nozzles or film heads associated with the conveyor 11 are maintained supplied with the film-forming material or coating substance through a system of piping from a reservoir which may be in the form of a collector sump maintained at the bottom of the casing or cabinet 42 and into which the liquid material issuing from the film heads may flow by gravity for continuous recirculation through the system. The specific arrangement of the piping will vary for different installations but for exemplary purposes, a system suitable for the present illustrated installation has been schematically shown in FIG- URE 7, wherein a manifold pipe is operatively connected through a series of six branch pipes 62 to the various film heads, and through additional branch pipes 64 and 65 leading to the opposite ends of the bottom coating apparatus 32. The molten liquid coating material is withdrawn from the sump 66 through a conduit 68 leading to the intake side 69 of a pump 70 driven by a motor 70 and the discharge side 71 of the pump 70 is connected through a conduit 72 to the manifold pipe 60. Replacement liquid may be supplied to the system by introduction thereof into the casing or cabinet 42 where it will find its way by gravity to the sump 66.

The film forming material is maintained slightly above its melting temperature at a point where the desired flow characteristics are exhibited, by suitable electrical heating apparatus. Additionally, in order to maintain the interior of the cabinet 42 at a constant even temperature and to provide a blanket of warm air over the inlet and outlet ends of the cabinet, 3. series of infra-red lamps 73 are provided. These lamps give uniform heating throughout the cabinet 42, and also afford visibility of the mechanism contained within the cabinet and facilitate inspection of the film characteristics which may obtain at any of the various film heads at any given instant. The heat generated by the heating instrumentalities 73 is to a large extent retained within the cabinet 42 and is uniformly distributed throughout the interior thereof where it serves to maintain the various moving parts at the proper working temperatures so that the wax, plastic or other film-forming material will not harden thereon.

Still referring to FIGURE 1, and in addition to FIG- URES 4, and 6, the film heads 44 and 46 are associated with the conveyor straightaway portion 26a and are disposed in longitudinally spaced relation along one edge of the conveyor band in or near the horizontal plane of the straightaway portion and are arranged to direct their respective liquid films f1 and 2 in a generally horizontal direction inwardly of the conveyor structure and across the upper face of the moving band 10. As shown in FIG- URES 1 and 4, the film f1 emerges or issues from the film head 44 and fans out, so to speak, in the form of a relatively thin generally planar liquid sheet or film. The effective angle of direction of the film head 44 is such that the upper edge of the film follows a generally parabolic path of motion similar to the trajectory of a projectile projected into space at the same angle. An approximation of the cross sectional area of the film is shown in FIGURE 5 and it will be noted that along the upper edge of the film there is a thickened portion 72 which is occasioned by a phenomenon which is termed herein as a rope effect inasmuch as it gives a visual simulation of a rope along the upper edge of the film. This so-called rope gives substance to the film and creates a body of the flowing liquid material from which liquid particles fiow across the film structure. The film also exhibits a rope effect as at 74 along its lower edge.

The pressure of liquid issuing from the nozzle or head 44 is sufficiently great as to carry the unbroken film completely across the width of the conveyor band 10 or, at least a sufiicient distance removed from the head that when the film is intercepted by the oncoming article A undergoing coating, the side or sides of the article opposing or facing the head will interrupt the film and establish a cut-off point 76 (FIGURE 4) while the portion 78 of the film not intercepted by the article will be carried completely over the top of the article so as to clear the same and allow the liquid film to be discharged downwardly within the cabinet or casing 42 in the general direction indicated by the arrows. The film f1 will maintain its unbroken continuity as it arches over the top of the moving article A and it will break as indicated at 80 at some region beyond the article into streams or droplets for subsequent collection in the sump 66.

As will become clear presently during the description of the mechanism shown in FIGURES 8, 9 and 10, means are provided for adjusting the angularity of the various film heads 44, 46, 48, etc., as well as for adjusting the'lateral positions of these film heads relative to the axis of the conveyor 11, Le, their distance from the said axis, such adjustments being provided to accommodate different installations, as well as to accommodate the shape characteristics of different articles undergoing packaging. In connection with the rectilinear articles A selected for illustrative purposes herein, the first nozzle or film head 44 in the series of film heads is arranged at the side of the conveyor band 10 so that the vertical plane of the film fl is inclined forwardly at an angle of from approximately 30 to approximately 45 with respect to the transverse direction of theconveyor, as clearly shown in FIGURE 1.

Hence, when the moving article A intercepts the film, a portion of the film will be applied progressively to the vertical side of the article which directly opposes or faces the film head 44 and, thereafter, as the article progresses along the axis of the conveyor, a portion of the film will be progressively applied to the trailing vertical side of the article.

For convenience of description, the four vertical sides of the article A have been designated a, b, c, and d, respectively, while the top and bottom faces of the article are designate-d at e and 1, respectively. The side a is the leading side of the article. The side c is the trailing side. The sides :5 and d are the right hand and left hand sides of the article, as viewed in FIGURE 1. Due to the forward inclination of the plane of the film f1, as previously described, it will be seen that as the article progresses through the vertical plane of the film, a portion of the film will be applied to the sides d and c progressively in the order named.

In connection with the application of the film 1 to the sides d and c of the articles A as just described, the pressure maintained at the film head 44, the viscosity of the liquid film, and the speed of travel of the article A along the axis of the conveyor, are so related to one another that the film will be applied to the surfaces of the article uniformly. In general, the linear speed of movement of the flowing film f1 and the linear speed of movement of the article A will be so correlated that the portion of the film intercepted by the article will be uniformly placed upon the sides of the article without appreciable film fiow on the surface of the article after the film has contacted the sides thereof. Where the article is allowed to exceed a certain predetermined rate of motion, there is danger of interrupting the continuity of the film as it is deposited on the surface of the article. Where the article does not proceed along the conveyor at a sufficient rate of motion, the film will build up on the surface of the article and flow downwardly on the surface of the article and flow downwardly on the surface in the manner encountered during conventional enrobing operations.

By properly adjusting the various factors mentioned above, both film interruption and film flow or bunching or portions of the film on the surface of the article will be avoided and a uniform film coating which accurately follows the contour of the surface of the article will be attained. It should be noted at this time that since the temperature of the film is maintained slightly above the melting point of the film substance, and since the articles are maintained at temperatures considerably below such melting point, especially in the case of frozen meat products, the applied relatively thin film coating will harden shortly after application to the surfaces of the article. The temperature maintained within the cabinet 42 and other temperature factors, conditions of film viscosity, speed of film projection and other physical phenomena are carefully controlled so that complete hardening of the applied coating issuing from the film head 44 will not take place before subsequently applied overlapping or joining films are applied to the article by the other film heads'so that a uniform and substantially homogeneous package coating will intimately be applied to the articles A.

It will be observed by an inspection of FIGURE 4 that during passage of an article A through the film f1, free flow of the liquid film in the lower regions thereof is interrupted by the left hand edge of the rectilinear article, while no obstruction is presented to such free flow of the film in the upper regions thereof. Since the direction of the film head 44 is such that the film possesses both vertical upward and transverse components of motion relative to the conveyor, the upper portion of the film will arch in parabolic fashion and pass completely across the article and span the conveyor band 10 with a sharp cutoff taking place at 76 as previously described and with the projectedv film portion 78 clearing the upper face of sesame 9 the article and leaving this face completely devoid of any film deposition.

Referring again to FIGURE 1, the article A which has emerged from the film f1 with a film coating on the sides d and thereof will subequently encounter the film f2. The film head 46 which supplies the film f2 is so positioned that the film has both an upward vertical component of motion and a transverse component of motion while the plane of the film is inclined rearwardly at an angle to the path of travel of the articles A. Due to such inclination of the film f2, it will be seen that as the article progresses through the vertical plane of the film, a portion thereof will be progressively applied sequentially to the side a and to the previously deposited film on the side d, in the order named. While a certain amount of solidification of the previously deposited film on the side d may take place during passage of the article from the film f1 to the film f2, due to contact of the film with the relatively cold product comprising the article A, such preliminary hardening will not prevent the two coatings uniting and forming a unitary homogeneous film mass which completely covers the side d. The same phenomenon of film cut-off and parabolic arching of the film over the top of the article A will obtain as the article encounters the film f2 and passes therethrough and this phenomenon need not be again described.

From the film f2, the article A, now fully coated on one side and with a partial completely coextensive coat ing on two other sides, will proceed along the conveyor 11 to the film f3 which issues from the nozzle 48. This latter nozzle is positioned centrally over the straightaway portion 26a of the conveyor band 10 and is arranged to direct its continuous liquid film of coating material generally downwardly onto the top surface of the article and at a slight forward inclination relative to a vertical transverse plane. The film f3 is generally fan-shaped as clearly shown in FIGURE 6 with thickened rope effects being present, as shown at 84, along the upper marginal edges of the film. Otherwise, the cross sectional characteristics of the film are similar to that which has been illustrated in FIGURE in connection with the film 1.

The lower portion of the film f3 is somewhat wider than the maximum transverse width of the article A and, since the film f3 and article A are substantially centered on the conveyor band, the forward edge of the article will initially penetrate the film and establish two cut-off points 82 and 83 where the film 3 is intercepted by the longitudinal upper side edges of the article A. As the article progresses through the plane of the flowing film, a coating will be progressively applied to the top surface e of the article, while the uninterrupted portions 86 and 88 of the film will clear the sides d and b with these portions breaking at 90 and 92 in the vicinity of the plane of the upper straightaway portion 26a of the conveyor.

From the film f3, the article A emerges with the four faces thereof, namely the faces a, c, d and e, at least partially coated coextensively and proceeds along the con veyor path to the bottom coating mechanism 32 by means of which a coating of the material is applied to the underneath face 1 in a manner that will be described subsequently. The partly coated article A is transferred from the straightaway portion 26a to the straightaway portion 26b as it traverses the bottom coating mechanism 32 and thereafter it encounters the film f4.

The nozzle 50 which produces the film f4 is positioned centrally above the straightaway portion 26a of the conveyor band 10 and is arranged to direct its continuous film of coating material generally downwardly onto the previously deposited film on the surface b of the article A at a slight rearward inclination relative to the vertical transverse plane of the conveyor 11. The character and shape of the film f4 is substantially identical with the character and shape of the film f3 and similar coating effects are obtained whereby the uninterrupted portion of 10 the film clears the sides b and d of the article A as previously described in connection with the film f3.

The opposite inclinations of the two films f3 and f4 insure complete coating of all sides of any pockets or shallow depressions which may be present in the upper face e of the article A, the film f3 accommodating the forwardly disposed walls of such depressions or pockets and the film f4 accommodating the rearwardly disposed walls of such depression due to the respective angles of impact of the films on the face 2 of the article. Upon emerging from the film f4, the article will be fully coated on the upper surface with a homogeneous film of the material of the desired thickness, with other full coatings existing on the sides d and bottom face f. Partial coatings will exist as previously described on the sides a and c.

The film f5, which is the next film encountered by the partly coated article A, is similar to the previously described films fl and f2, but it issues from the nozzle 52 at the right hand side of the conveyor band 10, as seen in FIGURE 1. The nozzle 52 imparts to the film f5 components of both upward vertical and transverse motion with the vertical plane of the film being inclined forwardly relative to the path of travel of the articles along the conveyor 11 so that as the film is intercepted by the partially coated article A, a coating will be applied to the previously deposited coating on the side a and a coating will be applied directly to the side b, with the coatings being applied progressively and in the order named. As is the case in connection with the films f1 and f2, cut-off and arching of the film f5 over the top of the article wherein the film completely clears the top of the article will obtain.

The article A emerges from the film f5 with either full or partial coatings coextensively covering the six sides thereof and with only the sides a and b remaining partially coated. The film f6, when encountered by the article A, supplies the final coating to the sides a and b by depositing the interrupted portion of the flowing film progressively onto these two sides in the order named, with cutoff and arching elfects being present as previously described in connection with the films f1, f2 and f5. The fully coated article A then emerges from the film f6 and is caused to move across the bottom film thickness control mechanism 43 and be deposited on the conveyor belt 36 from whence it may be conducted to a point of discharge.

Referring now to the details of the bottom coating mechanism 32 which is best illustrated in FIGURES 1 and 2, it will be seen that this mechanism is interposed between the two conveyor band sections 26a and 26b at the region 30 where the conveyor band 10 makes a dip as previously described. The dip 30 is produced by an elongated generally semi-cylindrical trough-like member which may be formed of stainless sheet steel and which has its open side presented upwardly. The member 100 extends across the conveyor with its ends suitably anchored in the machine framework and thus located a slight distance below the level of the straightaway portion 26 of the conveyor band 10. Also extending across the conveyor with their ends anchored in the machine framework are a pair of spaced parallel fixed bars 102 and 104, respectively. These bars are positioned substantially in the plane of the straightaway portion 26 and the conveyor band 10 passes forwardly over the rearmost bar 104 and then extends downwardly around the curved underneath side of the member 100 and proceeds up wardly where it passes over the fixed bar 102. From the above description, it will be seen that any given point on the moving conveyor band 10 will pass from the straightaway portion 26a over the bar 102 downwardly and upwardly around the member 100 and over the bar 104 and proceed along the straightaway portion 26b. The bottom coating mechanism 32 is disposed within the hollow of the trough-like member 100 and it includes an elongated rectilinear box-like casing 106 which may be formed of stainless steel sheet material having an imperforate bottom wall 108, upwardly and inwardly inclined front and rear walls 110 and 112, respectively, and a perforate top wall 114 provided with a plurality of small holes or openings 116. The holes 116 are preferably arranged in three parallel rows, although it will be understood, of course, that any desired arrangement of the holes may be resorted to, providing these spaced holes are well distributed throughout the area of the rectangular top wall 114. The casing 106 is provided with side walls 115 and 117, respectively, each of which is formed with an opening 118 therethrough in communication with the manifold pipe 60 through the previously mentioned branch pipes 64 and 65.

The level of the top wall 114 is maintained slightly below the level of the straightaway portion of the conveyor to afford a slight clearance for passage of the bottom wall 1 of the various articles A over the bottom coating mechanism 32 as the same are transferred from the conveyor straightaway portion 26a to the straightaway portion 2617. Liquid coating material introduced into the casing 106 under pressure will substantially fill the same and be forced outwardly through the various holes 116, as shown in FIGURE 2, to provide a series of closely spaced jets, streams, or the like, which are directed upwardly toward the bottom surface of the article passing thereover. These various jets serve to apply a coating to the bottom surface of the article and, in a sense, it may be said that the bottom coating arrangement thus serves to float the articles across the gap between the two straightaway portions 26a and 26b of the conveyor.

The bottom thickness control mechanism 43, Which is best illustrated in FIGURES 1 and 3, is in the form of a shallow vertically adjustable U-shaped bracket 120 having a base 122 and upstanding side flanges 124. Each side flange 124 has welded or otherwise secured thereto a lug 126 which threadedly receives therethrough an elevating screw 128 each screw being rotatably journalled as at 130 in a portion of the machine framework 20. The lower end of the elevating screws 128 carry bevel gears 132 which mesh with similar bevel gears 134 provided on a transverse shaft 136 suitably journalled in the machine framework 20. The upper end of one of the elevating screws 128 is adapted to receive thereon a crank arm 138 by means of which the screw may be turned in either direction to initiate raising the lowering movements of the bracket 120.

The bracket 120 constitutes a carriage for a plurality of horizontally disposed parallel idler rollers 140, the opposite ends of which are rotatably journalled as at 142 in the side flanges 124 of the carriage bracket 120. The elevation of the carriage bracket 122 is normally maintained at a point at which the rollers 140 are normally slightly below the plane of the upper surface of the straightaway portion 26 of the conveyor. The rollers 140 make actual contact with the underneath surface of the film and thus smooth out any irregularities that may occur on the surface of the film, and by vertically adjusting the height of the carriage bracket 122, the thickness of the bottom film may be controlled.

In FIGURES 8, 9 and 10, there has been illustrated one form of mechanism whereby the angularity of the various film heads 44, 46, 48, etc., may be adjusted within very fine limits to raise or lower the respective films produced thereby, and whereby the various film heads on opposite sides of the conveyor structure may be bodily shifted in unison inwardly or outwardly toward and away from the path of travel of articles on the conveyor band to accommodate articles of different widths. It will be understood, of course, that the means illustrated herein to effect these adjustments are purely exemplary and that other means for adjusting the positions of the nozzles may be employed if desired.

While in the schematic illustration of FIGURE 7 a single manifold pipe 60 supplies all of the film heads, the arrangement of FIGURE 8 involves the use of plural manifolds and 152, one for each set of film heads on opposite sides of the conveyor structure. Depending branch pipes 154 and 156 lead from the manifold pipe 150 to the film heads 44 and 46, respectively. Similarly, branch pipes 158 and 160 extend from the manifold pipe 152 to the film heads 52 and 54. The various branch pipes 154, 156, 158 and 160 are supported in individual supporting blocks 162 and these blocks on one side of the conveyor are carried on a rock shaft 164 and those on the other side of the conveyor are similarly carried on a rock shaft 166.

The two rock shafts 164 and 166 are each mounted for limited rocking movement in a pair of depending end flanges 168 provided on a supporting plate 170. The two supporting plates 170 are mounted for sliding movement toward and away from each other on a pair of guide rods 172 fixedly mounted on the machine framework 20. Each supporting plate 170 also has a pair of depending side flanges 174 through which the guide rods 172 extend so that the supporting plates 170 may he slid in either direction transversely of the conveyor assembly. Means operable under the control of a single crank arm, as will be described subsequently, are provided for selectively and regularly causing the two supporting plates 17 0 to be thus moved toward and away from each other transversely of the conveyor.

By virtue of the nature of the sectional piping which comprises the branch pipes 154, 156, 158 and 160, the film heads are capable of being angularly adjusted about the axes of their respective branch pipes. They are also capable of angular turning movement about their own longitudinal axes and thus, by combinations of the various adjustments of which the film heads are capable, the same may be collectively and individually adjusted through a wide range of positions.

In order to effect movement of the two supporting plates 170 toward and away from each other, each plate has mounted thereon a pair of spaced angle brackets and 182, respectively. The brackets 180 are adjustably carried on their respective supporting plates 170 for limited transverse adjustment and are capable of being clamped in any desired position of adjustment by clamping bolts 183. Extending through the two angle brackets 180 transversely of the conveyor assembly is an adjustment screw 184, the screw being threadedly received in the two brackets by means of threads of opposite pitch. Similarly, an adjusting screw 18 6 having threads of opposite pitch is threadedly received in the two angle brackets 182.

The two adjusting screws 184 and 186 are constrained to rotate in unison but in opposite directions by means of a pair of intermeshing gears 188 and 190 carried on the adjusting screws 184 and 186, respectively. The gear 188 is fixedly secured to the adjusting screw 184 while the gear 190 is slidably keyed to the screw 186 as at 192 so that this latter gear may be moved into and out of mesh with the gear 188, as desired. One end of the adjusting screw 186 is squared as at 194 for torque transmitting engagement in the socket portion 196 (FIGURE 10) of a suitable operating handle or crank 198 by means of which the adjusting screw 186, as well as the adjusting screw 184 when the latter is operatively geared thereto, may be turned in opposite directions.

From the above description, it will be seen that when the two gears 188 and 190 are in mesh as shown in FIG- URE 8, and the adjusting screw 186 is turned in one direction or the other, the supporting plates 170 will be constrained to move toward or away from each other as the case may be, thus carrying with them the manifold connections which they support, thereby increasing or decreasing the distance between the depending branch pipes on opposite sides of the conveyor structure and varying 13 the distance of the film heads from the center line of the straightaway portion of the conveyor.

Each bracket 182 is formed with a slot 200 therein into which slot there extends the distal end of a pin 202 carried on an arm 204 fixedly secured to one of the rock shafts 164 or 166 and thus it will be seen that when the gear 190 is moved along the adjusting screw 186 so that it is out of register with the gear 188 as shown in FIG- URE 10, and the clamping bolts 183 are loosened so that the brackets are free to move independently of the supporting plates 170 on which they are mounted, turning movement of the adjusting screw 184 in one direction or the other will cause the brackets 182 to be moved toward or away from each other, as the case may be, while the supporting plates 170 remain stationary. Such movement of the brackets 182 will be translated through the pins 202 to the arms 204, thus rocking the two rock shafts 164 and 166 in opposite directions and causing the pairs of branch pipes 154, 156 and 158, 160 to be swung toward and away from each other, thus varying the distance between the opposed sets of film heads as well as altering their angularity to a slight degree.

Although the specific construction of the film heads used to produce the films employed herein and designated f1, f2, f3, etc., may be of any desired nature, they all may be like the film head 44 specifically illustrated in FIGURE 11. The film head there shown is in the form of a unitary casting preferably formed of brass. It has a generally cylindrical configuration and is formed at one end with a threaded nipple 250 by means of which it may be threadedly received in the lower end of the branch pipe 154 with which it is associated. Immediately forwardly of the nipple 250, the casting is formed with a polygonal section 251, for reception of a wrench whereby the angularity of the film head as a whole may be adjusted about its axis.

The forward end of the casting is reduced, as at 252, and a recess 254 formed in one side thereof provides a proximate wall 256, a trough-like bottom 258 and a distal wall 260. A central bore 261 extends longitudinally inwardly from the threaded end of the film head and com municates with the recess 254 through a discharge orifice 262 which intersects the recess 254 adjacent the troughlike bottom 258 and in opposition to the distal wall 260. The distal surface 260 broadly comprises the liquid deflecting and film-controlling surface. This surface is more or less sharply curved adjacent to its base and it flattens out in the regions remote from the trough-like portion 258 into a planar surface which may be disposed at an angle of approximately 90 to the longitudinal axis of the film head casting.

Liquid issuing from the discharge orifice 262 is directed against the surface 260 near the base thereof in a concentrated central region. The impact of the stream of liquid issuing from the orifice 262 against the surface 260 causes the same to fan out, so to speak, and follow the contour of the surface 260, constantly changing its direction of travel until such time as it is thrown or forced radially outwardly from theedge regions of the surface 260, at which time a sheet of the liquid having diverging sides with rope-like effects as shown at 72 and 74 in FIGURES 4 and 5 is produced.

It will be understood that the specific shape of the deflecting surface may be varied to produce moving films which vary widely in film form or shape, film thickness,

film density and the like. Additionally, the angle which the planar portion of the surface 260 assumes relative to the longitudinal axis of the film head casting may be varied from a relatively small angle to an angle which 14 is deflected in passing from the orifice 262 into the body of the film.

To recapitulate, the streams of coating material dis charged from the nozzles of the so-called film heads, are in the form of thin, unbroken flat streams or flowing sheets of liquid fanning out from their respective nozzles and extending across the path of the advancing articles to be coated. Where each film or sheet crosses the path of the advancing articles it is large enough to have the articles pass therethrough between its divergent edges and still leave undisturbed an appreciable portion of the sheet between the articles and at least one edge thereof. Hence, the area of the portion of the sheet through which the articles pass is larger than the total projected area of the surfaces of the articles which oppose or face the sheet or film, either squarely or obliquely. The molecular content of the sheets or films moves generally horizontally inwardly of the path of the advancing articles, i.e., generally horizontally across said path, in the case of the sheets or films which coat the sides of the article, and generally downwardly onto the path in the case of the sheet or film which forms the top of the package.

The sheets or films which coat the sides of the articles are disposed at oblique angles of between 30 and 45 to the path of the articles, and the sheets or films which cover the top of the articles are slightly inclined. Thus, as the articles intercept the sheets or films, the intercepted portions thereof are laid unbrokenly onto the intercepting surfaces of the articles.

As will be readily apparent, the temperature inside the casing 42 must be sufficiently high to maintain the coating material in its liquid state. What this temperature should be depends upon the nature of the specific coating material. Where a microcrystalline wax is employed, this temperature should be in the neighborhood of 150 F. For other materials which possess a lower melting point, the temperature can be correspondingly less.

Whatever material is chosen for the coating, it should have a relatively low melting point, for instance F. to 350 F. and it must be hard enough at room temperatures to permit normal handling. Also, it should have a coeflicient of viscosity of at least 25 to 5000 centipoises when in its liquid film state. Best results are obtained when the viscosity is quite high, for then there is less likelihood that the sheet or film will break or vary substantially in thickness as it lays itself onto the surfaces of the article, which squarely or obliquely oppose the molecular flow of the film as the article intercepts it.

The selection of a suitable coating material and of the temperature needed to maintain it in a liquid state, as well as the pressure required to form it and maintain it in a flowing sheet or film will present no difficulty to those skilled in the art. By the same token, no difficulty will be experienced in coordinating the rate of flow of the liquid forming the sheet with the rate of advance of the articles. Obviously, if the articles advance too fast the film laid thereon may be too thin or even broken, and if the advance of the articles is too slow, the coating material will tend to pile up on the intercepting surfaces thereof. The ideal condition is one in which the intercepted portion of the film is deflected out of the plane of the sheet and laid unbrokenly, and without change in thickness, onto the opposing surfaces of the article, where it immediately begins to congeal.

The improved embodiment The embodiment of the invention illustrated in FIG- URES 12 to 19, inclusive, is a substantial improvement over the machine thus far described. Primarily, the improvement resides in providing a gap in the conveyor, or more accurately, in the article supporting portion or stretch thereof, at every one of the film heads or nozzles, and so disposing the nozzles that the films or sheets issuing therefrom have their lower portions received in these gaps. This feature is especially important in the case of the films or sheets which flow across the conveyor from its opposite sides, since it allows the heavier or thicker lower edge portions of the films or sheets, hereinbefore referred to as ropes to flow in an unbroken and undisturbed condition, and not strike any part of the articles or goods. As a result, the lower edges of the package are as neat and smooth as its top edges.

However, the reception of the lower portion of the downwardly flowing film or sheet by which the top surface of the article is coated, in a gap in the conveyor is also significant and advantageous; and to this extent the machine disclosed in the aforesaid application, and which appears herein in FIGURES 1 through 11, partakes of the improvement about to be described. In that machine, one of the downwardly directed films, specifically the film f4, enters the gap 30 between the conveyor sections 26a and 2611, or is at least discharged onto the bottom coating unit 32 which is located in the gap or dip as it has been referred to.

But now specifically considering the improved embodiment of the invention, it will be seen that the articles or goods to be packaged are fed into the machine by a feed conveyor 300, which leads to an entrance opening 301 in a cabinet 302 in which the instrumentalities of the machine proper are housed. The cabinet 302 is equipped with suitable heating means (not shown) by which the temperature therein is kept sufliciently above room temperature to assure the coating material being in its liquid state. What that temperature should be depends upon the specific characteristics of the coating material, as explained hereinbefore.

The entrance opening 301 is in one of the two opposite end walls of the cabinet; the other end wall has an exit opening 303 through which the coated articles or goods leave the cabinet to be deposited upon a delivery conveyor 304. The delivery conveyor 304, like the feed conveyor 300, may be of the belt type, and both are driven to travel at the same speed as the conveyor which is inside the cabinet and designated generally by the numeral 305. The delivery conveyor deposits the articles or goods upon a final receiving conveyor 306 which forms part of a cooling unit 307 by which the finished packages are cooled .to permit immediate handling. The cooling unit may include a blower by which cooling air is blown upwardly through the conveyor 306 which must be perforate, and which is positively driven at a rate slower than the other conveyors to gain a relatively long cooling time without unduly increasing the length of the conveyor 306. It is, of course, understood that the articles or goods on the conveyor 306 are more closely spaced than they are during their travel through the cabinet.

Directly after the articles or goods enter the cabinet their bottom surfaces are coated or covered with coating material, and preferably at the same time the top surfaces are coated. By having the bottoms coated immediately, maximum protection is given the articles or goods, since thereafter no part thereof comes in contact with the conveyor. But coating the bottom and top before any of the sides are coated has still another advantage. It assures a better and stronger bond between the top, bottom and sides of the shell or sheath by which the product is enveloped, and in fact produces a desirable multiple thickness head along all edges and corners of the finished package, as will be explained more fully hereinafter.

The conveyor 305 comprises a plurality of side-by-side endless conveyor elements 308a to 308f. In the specific structure shown, these conveyor elements are made of ladder chain, though, of course, any other suitable type of flexible material may be employed-narrow belts for instance. In any event, the side-by-side conveyor elements coact to provide an article support which is wide enough to carry the articles or goods for which the machine is designed, and by which the articles or goods are advanced 15 through the cabinet from its entrance to its exit, and in their travel pass first through a bottom and top coating zone or station, next through a series of side coating zones or stations, and then through a final bottom coating zone or station.

Each of the chains or conveyor elements 308a to 308 may consist of a single endless loop, but tofacilitate driving the same, each conveyor element is preferably divided into twoseparate loops, as clearly shown in FIGURES 15 and 16. More important though, is the fact that each conveyor element has a plurality of interruptions in its article supporting or top stretch, and these interruptions in the several conveyor elements are transversely aligned to form the desired gaps in the conveyor surface. There are six of these gaps, designated 309a to 30%, the first and last extending straight across the conveyor and the rest extending obliquely thereacross- The first gap 309a has the initial bottom coating device 310 mounted therein, the last gap 309 has the final bottom coating device 311 mounted therein, and the four obliquely extending gaps 30% to 3090 receive the side coating films or sheets projected from appropriately located nozzles 312b to 312e. As will no doubt be appreciated, it is the division of the conveyor 305 into sideby-side units which enables the gaps 30% to 30% to be disposed at oblique angles across the conveyor surface.

The flexible endles conveyor elements or chains are supported by and ride upon stationary tracks 313a to 313 suitably fixed in the cabinet or frame of the machine. Each of these tracks is preferably a stamping having a flat vertical body or web portion 314, (FIG. 17), a horizontal top flange 315 which forms the track proper, and an inclined stiffening flange or head 316 at the bottom edge. Where the gaps are to be located, the tracks have their upper portions cut out or interrupted, as at 317, and the adjacent ends of the top flange 315 which flank these cutouts or interruptions are bent down as at 318 to provide smooth rounded surfaces over which the conveyor elements travel as they dip down and return to their article supporting level.

At each of the gaps except the gap 3090, there is an idler sprocket 319 freely rotatably mounted on each of the tracks. These idler sprockets-they would be idler pulleys if the conveyor elements were round or narrow beltsare located wholly below the track level and are of such size that by having the conveyor elements (chains) passing down and under them, they coact with the adjacent track ends 318 to hold the conveyor elements out of the gaps, or in other words, to define the gaps.

At the gap 3090, no idler sprockets like the sprockets 319 are needed since this gap is formed by the division of the conveyor elements into two separate units.

The endless conveyor elements or chains also travel over other idler sprockets 320-323, freely rotatably mounted on the tracks near their bottom edges and over drive sprockets 324 and 324; and for each conveyor eletrnent or chain there is a spring actuated tightne-r 325 over which it runs, the tightners also being carried by the tracks.

The drive sprockets 324-324 are, of course, aligned, being fixed to cross shafts 326326, respectively. These shafts are journalled in bearings 327-327 and have worm wheels 328-328 fixed thereto. The worm wheels mesh with worms 329-329 respectively, which are fixed to a longitudinally extending drive shaft 330. This shaft is suitably driven in any desired manner, and thus actuates all of the drive sprockets to drive all of the conveyor chains in unison. As noted hereinbefore, each endless conveyor is divided into two units, each with its own drive, merely to simplify the driving means and to avoid the consequences of having the individual endless conveyor chains too long; but such division of the conveyor elements is not necessary. It is merely a matter of convenience.

By the Same token, the gaps in the conveyor could be produced by dividing each conveyor element into as many separate units as needed. The gaps in that case would be formed as is the gap 3090 by the endwise separation of the separate conveyor units.

As noted hereinbefore, the important thing about the gaps is that they enable the films or sheets which are projected transversely across the path of the advancing articles and other goods, to have their lower edges well below this path so that no portion of the films or sheets contacted by the articles or goods will be any thicker or heavier than the rest, as would be the case if the thicker lower edge or rope at the bottom of the film or sheet were permitted to strike the articles or goods. In other words, the presence of a gap in line with each of the nozzles 312b to 312e, extending obliquely across the conveyor, allows the lower edge portion of the film or sheets issuing from these nozzles, and particularly the heavier rope defining this edge, to move uninterruptedly across the conveyor well below the level of the conveyor top. As a result, the coatings applied to the side surfaces of the articles or other goods as they progress through the machine, will have uniform thickness over the entire area thereof, and will form themselves about and become neatly welded to the edges of the bottom coating as well as they are to the top coating. This condition is illustrated in FIGURE 17.

Of course, to achieve the condition shown in FIGURE 17, the nozzles 312b, to 3122 must be properly placed both with respect to the level of the conveyor top and the location of the gaps, but this is merely a matter of adjusting the nozzles.

The bottom coating device 310 which is located in the first gap 309a comprise a tube 331 which is preferably square in cross section, and has a plurality of small holes 332 in its top wall through which the coating material issues in upwardly projected jets. The coating material enters the tube from both ends since both are suitably connected with the source of pressurized liquid coating material, and to assure uniform pressure at all of the jets, the tube is progressively constricted from each end towards the middle thereof. This is conveniently accomplished by making the tube in the form of a U-shaped body having a divergently sloping bottom 333 and closing the top of the body by a separate plate 334 in which the holes 332 have been formed.

The tube 331 is removably mounted in place, in the first gap 309a with its perforated top wall slightly below the conveyor level, by having the ends of the tube seated in sockets formed in the upright flanges 335 of a pair of side rails 342 which may constitute part of the frame of the machine. The flanges 335 also freely rotatably mount a roller 336 alongside the tube 331 at its downstream side, with the top of the roller tangent to the conveyor level. Accordingly, the coating applied to the underside of the articles is smoothed out by this roller as the articles ride across it, it being understood that the roller, like the bottom coating tube, i received in the gap 309a.

The final bottom coating device 311 may be identical in construction to the one just described, but it alone occupies the last gap 309/. The final bottom coating layer applied by this unit is smoothed or ironed by a pair of freely rotatable rollers 337, which are carried by a bracket 338 fixed to the flanges 335 of the side rails 342.

Referring to FIGS. 20 and 21, a modified bottom coating device is illustrated which differs from the devices 310 and 311 in merely providing a film coating nozzle 350 directing a thin planar film or sheet of material 351 upwardly through a gap 352 arranged between adjacent conveyors defining a bottom coating station. This device may be substituted for one or both of the devices 310 and 311. Essentially, the film 351 emanating from the nozzle 350 may be the same as that produced by the nozzle 312, and the film 351 may extend upwardly at any angle such as like that illustrated. And the nozzle 350 may be like the nozzle 312 or the nozzle 48 or any other suitable type capable of producing a film.

The several side-by-side tracks 313a-313f may be held in properly spaced relation in any suitable manner, and in the structure shown are so held by tie rods 340 extending through the vertical webs of all of the tracks and through suitable spacers 341. The tie rods may also be used to mount the entire conveyor assembly in the machine, in which case the ends of the tie rods are fixed in the vertical flanges 335 of the side rails 342.

The manner in which the various nozzles are connected with the source of pressurized liquid coating material need not be discussed, since this simply involves suitable plumbing. Likewise, the manner in which the nozzle 343 from which the top coating film or sheet issues, need not be dealt with in detail, sutfice it to say that this nozzle, like the nozzle 50 in the previously described embodiment of the invention, is positioned to direct its film or sheet down onto the adjacent bottom coating device 310, which is located in the first gap 309a.

For some difficult to handle thermoplastic materials, the top coating film or sheet is projected down into a separate gap as shown in FIGURE 19, i.e., the gap into which this film or sheet is directed does not contain a bottom coating unit, but instead only has a collecting trough 345 disposed therein to receive the liquid film material which is not laid onto the passing articles and which, of course, continues to flow as long as the machine is in operation whether or not articles are being passed through it. The trough 345 is of special design and construction to assure retention of the coating material in its liquid state, but since this feature forms no part of the present invention, it has not been shown.

From the foregoing description taken with the accompanying drawings, it will be apparent to those skilled in this art that the machine of this invention particularly the improved version thereof, provides a practical and highly expeditious apparatus for practicing the new packaging method covered by the aforesaid application, now Patent No. 3,008,834.

It will be understood that modifications and variations may be efiected without departing from the scope of the novel concepts of the present invention, but it is understood that this application is to be limited only by the scope of the appended claims.

What is claimed as my invention is:

1. In a packaging machine for applying a protective air-tight sheath of coating material which is a solid at ordinary room temperatures and a viscous liquid at elevated temperatures, to any article having sufiicient rigidity to be self supporting, the combination of: a cabinet in which the temperature may be maintained high enough to keep the coating material liquid, the cabinet having spaced upright end walls with entrance and exit openings therein; endless conveyor means inside the cabinet providing a substantially horizontal article support movable in one direction to carry articles along a defined path from the entrance to the exit of the cabinet, said article support being comprised of lengthwise adjacent sections separated by a gap across which articles on the support must travel; and means lateral of said support to project a stream of the coating material across the path of the articles being carried on said support, including a nozzle from which the stream of coating material issues; the nozzle having means to shape the stream into a substan tially fiat sheet with diverging edges, and means mounting the nozzle in a position in which it causes the sheet to assume an upright disposition with the lower portion thereof in said gap and well below the level of the article support so that the path of the articles on the support intersects the sheet above the bottom edge thereof.

2. In a packaging machine for applying a protective air-tight sheath of coating material which is a solid at ordinary room temperatures and a viscous liquid at elevated temperatures, to any article having sufficient rigidity to be self supporting, the combination of: a cabinet in which the temperature may be maintained high enough to keep the coating material liquid, the cabinet having spaced upright end walls with entrance and exit openings therein; endless conveyor means inside the cabinet providing a substantially horizontal article support movable in one direction to carry articles along a defined path from the entrance to the exit of the cabinet, said article support being comprised of lengthwise adjacent sections separated by a gap across which articles on the support must travel, and each section of the article support comprising a plurality of side-by-side endless conveyor elements, said conveyor elements of one section being aligned with and paired with those of the other section, and the adjacent ends of said paired conveyor elements being located at different distances from said spaced end walls but in a straight line across the width of the article support so that said gap between the endwise adjacent sections of the article support is obliquely transverse to the path of the articles; and means lateral of said conveyor elements to project a stream of the coating material across the path of the articles being carried on said support, including a nozzle from which the stream of coating material issues; the nozzle having means to shape the stream into a substantially flat sheet with diverging edges, and means mounting the nozzle in a position in which it causes the sheet to assume an upright disposition with the lower portion thereof in said gap and well below the level of the article support so that the path of the articles on the support intersects the sheet above the bottom edge thereof.

3. In a machine for applying a protective air-tight sheath of coating material which is solid at ordinary room temperatures and a viscous liquid at elevated temperatures, to any article having sufficient rigidity to be self supporting, the combination of: conveyor means to carry the articles through the machine, said conveyor means comprising a plurality of side-by-side parallel substantially horizontal stationary tracks on a common level, each of said tracks being interrupted at a plurality of locations, and the interruptions in adjacent tracks being transversely aligned, endless conveyor elements slidably supported on said tracks to collectively provide a moving article support, means at the track interruptions guiding and com straining said conveyor elements to move in paths which drop well below the level of the tracks at said interrup tions so that at each group of transversely aligned track interruptions a gap occurs in the moving article support across which the articles travel as they are advanced by the endless conveyor elements; means to drive all of the endless conveyor elements in unison; and means including a nozzle lateral of the conveyor means and aligned with each gap in its article support to project a flowing sheet of the coating material across the conveyor with each said sheet disposed substantially vertically and having its lower edge in the adjacent gap in the article support and below the level thereof.

4. The combination set forth in claim 3, wherein the locations of certain of the transversely aligned track inter ruptions are staggered with respect to one another lengthwise of the tracks in a straight line across the tracks so that the gap formed thereby extends diagonally across the article support.

5. The combination set forth in claim 3, wherein each track comprises a flat bar set edgewise and in a vertical plane, and having a flat horizontal flange along its upper edge, said flange forming the track proper and having the endless conveyor element riding thereon, the track interruptions being formed by cutouts in the upper portion of the bar and through its flange, and the flange portion flanking each interruption being bent down to form smooth rounded surfaces over which the conveyor element rides as it leaves and/or rides onto the track.

References Cited by the Examiner UNITED STATES PATENTS 1,202,146 10/ 1916 Balcar 1l824 1,230,455 6/1917 Bausman 118-16 1,872,507 4/1930 Saunders et al. l183 14 2,543,277 2/1951 Copeman 118-316 X FOREIGN PATENTS 330,927 6/ 1930 Great Britain.

DANIEL BLUM, Primary Examiner. 

1. IN A PACKAGING MACHINE FOR APPLYING A PROTECTIVE AIR-TIGHT SHEATH OF COATING MATERIAL WHICH IS A SOLID AT ORDINARY ROOM TEMPERATURES AND A VISCOUS LIQUID AT ELEVATED TEMPERATURES, TO ANY ARTICLE HAVING SUFFICIENT RIGIDITY TO BE SELF SUPPORTING, THE COMBINATION OF: A CABINET IN WHICH THE TEMPERATURE MAY BE MAINTAINED HIGH ENOUGH TO KEEP THE COATING MATERIAL LIQUID, THE CABINET HAVING SPACED UPRIGHT END WALLS WITH ENTRANCE AND EXIT OPENINGS THEREIN; ENDLESS CONVEYOR MEANS INSIDE THE CABINET PROVIDING A SUBSTANTIALLY HORIZONTAL ARTICLE SUPPORT MOVABLE IN ONE DIRECTION TO CARRY ARTICLES ALONG A DEFINED PATH FROM THE ENTRANCE TO THE EXIT OF THE CABINET, SAID ARTICLE SUPPORT BEING COMPRISED OF LENTHWISE ADJACENT SECTIONS SEPARATED BY A GAP ACROSS WHICH ARTICLES ON THE SUPPORT MUST TRAVEL; AND MEANS LATERAL OF SAID SUPPORT TO PROJECT A STREAM OF THE COATING MATERIAL ACROSS THE PATH OF THE ARTICLES BEING CARRIED ON SAID SUPORT, INCLUDING A NOZZLE FROM WHICH THE STREAM OF COATING MATERIAL ISSUES; THE NOZZLE HAVING MEANS TO SHAPE THE STREAM INTO A SUBSTANTIALLY FLAT SHEET WITH DIVERGING EDGES, AND MEANS MOUNTING THE NOZZLE IN A POSITION IN WHICH IT CAUSES THE SHEET TO ASSUME AN UPRIGHT DISPOSITION WITH THE LOWER PORTION THEREOF IN SAID GAP AND WELL BELOW THE LEVEL OF THE ARTICLE SUPPORT SO THAT THE PATH OF THE ARTICLES ON THE SUPPORT INTERSECTS THE SHEET ABOVE THE BOTTOM THEREOF. 